How do you follow up an earth-shattering hit like Angry Birds? Not with Amazing Alex, Rovio's first property to branch out of their only previous IP. The game currently sits with only a tiny fraction of the downloads of Angry Birds, even on the free version. So with the third go-round, they've gone back to create a spinoff featuring the antagonists of the aggravated avians: Bad Piggies. The new game is a combination of the previous two, combining the simple physics-based goals of Angry Birds and the contraption building of Amazing Alex.

So, do the pigs deliver? Certainly. Rovio's strength is in simple premises that become more and more complex, and Bad Piggies exemplifies this ethos, while adding more complexity and variation than either of the previous titles. Bad Piggies will rack up tens of millions of downloads no matter what I write here, but if you're wondering whether it's worth your time, it certainly is. However, there are a few concerns that may annoy gamers - especially Angry Birds fans.

Gameplay

Think of Bad Piggies as a variation on the Rube Goldberg-inspired board game Mouse Trap. You have to build a contraption to get your pig to the finish line, using both your materials and the environment to reach the goal. But instead of building the trap, you're the mouse, building an improvised vehicle with the modular containers, wheels and propulsion provided in each level. Place your pig inside the vehicle, set it off, control its progress through the level, and try to get to the finish line in as few pieces as possible.

Most early levels require a pine cart derby approach: build a vaguely rectangular device and let it roll towards your destination. At first you're only given modifiers for propulsion: bellows, Coke-and-Mentos, umbrellas. Your means of movement gets progressively zanier, and soon you'll have to carefully open or close umbrellas to let gravity work for you, or even strategically set off TNT to send your pig flying towards the goal. As the first set of levels progress, you're eventually given access to motors, then more and more powerful engines. The stages become a combination maze and racetrack, and you'll have to carefully apply the different means of motion as you go along.

The second chapter, "When Pigs Fly," lets the developers really spread their wings. This one's all about getting airborne and controlling your vertical and lateral movement, keeping your pig aloft by attaching and then popping balloons or dropping sandbags. Eventually you're given airfoils and tails. The structures get more and more crazy - not to mention difficult - but with enough trial and error and a grasp of the 2D game's physics most players should reach the end of the 70 levels eventually.

Pork In The Barrel

Once you finish the main game, you've always got the ability to go back and try for three stars on all levels, as hardcore Angry Birds players are quite familiar with. There's no set score here: modifiers to achieve stars can be different for each level. You always have to cross the finish line with your pig, but you can earn stars by picking up the bonuses in the stages, finishing under a certain time limit, or reaching the end with your contraption intact. This time around the extra goals are cumulative, so you don't have to get all of them in one run. Golden Eggs have been replaced with pig skulls, for some reason.

But the real replay value comes in a new game mode: Sandbox. As you go through the main levels you'll be awarded different parts to use in the Sandbox, huge single levels with no goal, no time limit, and nothing but stars to collect. This is where you can build virtually unlimited vehicles to go as fast and as high as you want, at least after you've completed the main stages. It's a brilliant addition, as those who get the most enjoyment out of getting their vehicles right in the main game could waste hours here. The stages for the Sandbox only unlock after you complete enough of the main game.

Graphics and Audio

Visuals are typical Rovio: colorful, with solid animation and ingratiatingly cute spheroid protagonists. Those who were fans of the style in the various Angry Birds incarnations will not be disappointed. That being said, the sparse instructions sometimes aren't enough. It's difficult to tell what the various contraptions do until you start them, and the icons for the level goals aren't much help. An visual "guide" of sorts is somewhat useful, but it's almost as Spartan as the rest of the game.

What music and story is there is pretty thin, but enjoyable. Thankfully the God-awful squawking from Angry Birds is replaced by the much more mellow grunts of a single pig, and the music doesn't stick in your head forever (a good thing, at least in my opinion). With only two chapters available at the moment, there's not much variation, but you can bet that more is coming.

Performance was mostly good, but it's clear that Bad Piggies could use a little more polish. Even on my Transformer Prime testing hardware, the game would often slow down or stutter, and it crashed twice. I'm sure these issues will be resolved soon enough, but it's a little disheartening to see this kind of stuff in such a hyped-up game. There are tiny variations in the physics system that also need to be ironed out. It's possible to have two runs with exactly the same variables and different outcomes - something that shouldn't be happening.

Piggy Bank

Right now there's only two ways to play Bad Piggies: the free standard version, and the also free HD version for tablets or newer smartphones. Android users, unlike their iOS counterparts, have no option to pay for an ad-free experience. It's disappointing after having both free and premium options for Angry Birds Space and Amazing Alex. That said, the ads have only appeared on the menus while I've played the HD version.

Another monetization vector comes in the form of in-app payments, but these were so blessedly unobtrusive that they can be safely ignored. For a couple of dollars (sadly Facebook credits, not Google Play native in-app payments) you can enlist the aid of a piggy engineer, who will help you build the right vehicle for the job.

Like its predecessors, Bad Piggies monetizes in a way that's almost transparent. Even so, I'd like the option to pay for an ad-free experience, and it's a shame that Android users are being denied the option.

Conclusion

Bad Piggies isn't perfect - it's clear Rovio was a little eager to get this one out the door, and it's definitely showing a few cracks in the veneer. And not everyone will like it, especially if you're looking for something as dead simple as Angry Birds. In the virtual offices of Android Police, opinion was divided.

But as far as I'm concerned, it's a solid and thoughtful effort for Rovio's tertiary game. It's got the approachability of Angry Birds and (eventually) the complexity of Amazing Alex, with the addictive, "one more try and then I'll go to bed" quality that a mobile hit needs. If Bad Piggies was a little more stable and had a little more thought in its UI, it would approach the best of the best. But as it stands, it's certainly worth a free download for any Android users looking for a pick-up-and-play distraction.